Myopathy Followed by Rash in a Young Boy: Classic Signs?

July 11, 2014

A 5-year-old boy had pain and weakness in his legs and had trouble climbing stairs. He had a dramatic rise in CPK followed by erythematous papules on the hands, as shown, and a rash around the eyelids. Which diagnosis is most likely?

A 5-year-old boy was having difficulty in walking up stairs; he complained of pain and weakness in both legs. His CPK had risen from 1252 U/L to 1400 U/L in 2 weeks. His CBC was normal. Two months later, these papules developed over his proximal and distal interphalangeal and metacarpophalangeal joints along with an erythematous rash around the eyelids.

Which diagnosis is most likely?